The invention is directed to improvements in brake fluid containers for hydraulic brake systems in motor vehicles.
Such containers serve as the fluid reservoir for two or more separate brake circuits of the brake system, with the chambers associated with the individual brake circuits being filled in common via a fill connector. A single level switch detects the fill level in the container and emits a visual and/or acoustical signal if the fluid level drops to a predetermined minimum value. The container either communicates with the master brake cylinder of the brake system via lines, or else is united directly with it.
In a known brake fluid container of this type (U.S. Pat. No. 4,337,792), the level switch, which includes an electrical switch contact and a float actuating the switch and plunging into the brake fluid, is secured to the container cap that closes off the fill connector; if the container cap is removed, to fill or refill the container with brake fluid, the level switch is pulled out of the fill connector. The fill connector is closed off to make two separate chambers by means of a single cup-like fluid filter, which is inserted into the fill connector and prevents soil particles from entering the two fluid chambers along with the brake fluid. The float is axially displaceably mounted on a rod secured to the container cap and assumes a position in accordance with the fill level in the fill connector; the float magnetically closes a switch contact when the lowest allowable point of the fluid level is reached.
A level switch of this kind is vulnerable to severe fluctuations in the brake fluid in the container, which occur during cornering and upon major acceleration and braking of the vehicle. In such cases, the level switch often consequently closes and produces annoying readings.
In another known brake fluid container (German Pat. No. 30 38 947) the level switch is disposed in a chamber that is separate from but communicates with the other chambers. The float is displaceably guided on a rod that is secured to a cap closing off an opening in the chamber. The switch chamber, defined by especially shaped walls, is disposed in the central, middle region of the housing, to minimize the effects of inclination, acceleration or braking on the fluid level in the switch chamber.